source: trunk/gcc/libjava/java/awt/event/ComponentEvent.java

/* ComponentEvent.java -- notification of events for components
   Copyright (C) 1999, 2002 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */


package java.awt.event;

import java.awt.AWTEvent;
import java.awt.Component;

/**
 * This class is for events generated when a component is moved, resized,
 * hidden, or shown.  These events normally do not need to be handled by the
 * application, since the AWT system automatically takes care of them. This
 * is also the superclass for other events on components, but
 * ComponentListeners ignore such subclasses.
 *
 * @author Aaron M. Renn <arenn@urbanophile.com>
 * @see ComponentAdapter
 * @see ComponentListener
 * @since 1.1
 * @status updated to 1.4
 */
public class ComponentEvent extends AWTEvent
{
  /**
   * Compatible with JDK 1.1+.
   */
  private static final long serialVersionUID = 8101406823902992965L;

  /** This is the first id in the range of ids used by this class. */
  public static final int COMPONENT_FIRST = 100;

  /** This is the last id in the range of ids used by this class. */
  public static final int COMPONENT_LAST = 103;

  /** This id indicates that a component was moved. */
  public static final int COMPONENT_MOVED = 100;

  /** This id indicates that a component was resized. */
  public static final int COMPONENT_RESIZED = 101;

  /** This id indicates that a component was shown. */
  public static final int COMPONENT_SHOWN = 102;

  /** This id indicates that a component was hidden. */
  public static final int COMPONENT_HIDDEN = 103;

  /**
   * Initializes a new instance of <code>ComponentEvent</code> with the
   * specified source and id. Note that an invalid id leads to unspecified
   * results.
   *
   * @param source the source of the event
   * @param id the event id
   * @throws IllegalArgumentException if source is null
   */
  public ComponentEvent(Component source, int id)
  {
    super(source, id);
  }

  /**
   * This method returns the event source as a <code>Component</code>. If the
   * source has subsequently been modified to a non-Component, this returns
   * null.
   *
   * @return the event source as a <code>Component</code>, or null
   */
  public Component getComponent()
  {
    return source instanceof Component ? (Component) source : null;
  }

  /**
   * This method returns a string identifying this event. This is the field
   * name of the id type, and for COMPONENT_MOVED or COMPONENT_RESIZED, the
   * new bounding box of the component.
   *
   * @return a string identifying this event
   */
  public String paramString()
  {
    // Unlike Sun, we don't throw NullPointerException or ClassCastException
    // when source was illegally changed.
    switch (id)
      {
      case COMPONENT_MOVED:
        return "COMPONENT_MOVED "
          + (source instanceof Component
             ? ((Component) source).getBounds() : (Object) "");
      case COMPONENT_RESIZED:
        return "COMPONENT_RESIZED "
          + (source instanceof Component
             ? ((Component) source).getBounds() : (Object) "");
      case COMPONENT_SHOWN:
        return "COMPONENT_SHOWN";
      case COMPONENT_HIDDEN:
        return "COMPONENT_HIDDEN";
      default:
        return "unknown type";
      }
  }
} // class ComponentEvent